1. Field of the Invention
The invention relates to a driving assistance technique.
2. Description of Related Art
There is known a driving assistance apparatus that includes obstacle detecting means (for example, an ultrasonic sensor, a millimeter wave radar, or the like) for detecting an obstacle around a vehicle and that avoids a collision by executing automatic braking control irrespective of driver's operation, for example, when a distance to the obstacle is shorter than or equal to a predetermined distance.
In the driving assistance apparatus, if the vehicle turns in a state where there is an obstacle around the host vehicle, the driving assistance apparatus may erroneously recognize that there is an obstacle in a traveling direction although there is no obstacle in the traveling direction, and may execute the above-described automatic braking control for avoiding a collision. For example, there is a case where, at the time when the vehicle makes a U-turn while moving close to a wall at the side of a road, the driving assistance apparatus may execute automatic braking control because the distance between the wall and the host vehicle becomes shorter than or equal to the predetermined distance although there is no wall in the traveling direction.
Automatic braking control in this case is unnecessary for the driver; on the contrary, there is a concern that the driver experiences a feeling of strangeness. Therefore, there is suggested a technique for not activating automatic braking control at a predetermined steering angle or larger (for example, Japanese Patent Application Publication No. 2007-145315 (JP 2007-145315 A)).
However, if automatic braking control is not activated uniformly at the predetermined steering angle or larger, there may occur an inconvenience. For example, this is the case where the vehicle is parked in a state where a steering wheel is turned, the driver shifts into a shift position intended for a direction opposite to a direction in which the driver intends to start moving the vehicle and then the driver depresses an accelerator, or the case where the driver erroneously depresses the accelerator in mistake for a brake at the time when the driver starts moving the vehicle and then attempts to avoid a collision with an obstacle by operating the steering wheel immediately before the collision. In such cases, it may not be possible to effectively avoid a collision by uniformly not executing automatic braking control at the predetermined steering angle or larger.